Geabr-shefting mechanism



C. E. F. AHLM GEAR SHIFTING MECHANISM Dec. 28 1926.

Filed July 8, 1925 2 Sheets-Sheet l Vle.-

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Dec. 28, 1926.

1,611,865- c. E. F. AHLM GEAR SHIF'IING .MECHANI SM 2 Sheets-Sheet '2 Filed July 8, 1925 ,r'ertifveness and certainty of operation.

Patented Dec. 28, 1926.

CHARES E. iF. .AI-ILM,

0E CLEVELAND, OHIO.

GEAR-SHIFTING MECHANISM.

Application filed July 8,

rlhis invention relates to gear shifting n'iechanism, and the object is to provide a simple and convenient arrangement for effecting a quel; and easy slide shift of gear or clutch members tochange from one speed to another.

More specifically, it is an object to combine the usual longitudinal and transverse niorvement required of an operating member to selectively engage and shift a pair of independently shifta-hle membersiinto one uni-` lirectional moven'ient, while n aiutaining ef- A further object is to combine with such mechanism means for preventing the accidental shifting of one of a pair of longitudinally shiftable men'ibers when the shifting member therefor is in engagement with the other of theipair. A further specific object is to provi-de a gear shifting mechanism in which the necessary longitudinal and tran?- verse movement of a memlgier cooperating selectively with two movable members is translated to a straight forward and backward movement of a hand lever.

Further objects and features of myvinvention will appear in the detailed descrip tion that follows which relate to the accompanying drawings. The essential novel characteristics are set out in theclaims.

.fr 'very widely used form of shifting mechanism includes a pair of slidable bars suitably connected to the gear or clutch members to-be shifted, each bar being provided with open throats for receiving the end of a shifting lever and means such a guide plate is comn'ionly used to direct the path of the shifting lever into and out of the desired throat and guidel the lever while n'iaking the shift. The type of guide usually employed comprises a plate,y having an H shaped opening therethrough. lf it is desired to shift one bar in one direction from a given position, and the other in the oppir site direction, only the diagonally opposite arms of the H are provided. My invention isV particularly concerned with this latter type.

The guide plate which I propose to use has a lever guide opeliiiig in the nature. of a vcompound curve so arranged that the manual operation of the lever may simply necessitate a general forward or backward moven'ient to etl'ect a complete shift of both bars` as coiitracted with a forward crosswise and further forward .movement necessi- 1925. Serial N0. 42,132.

tated by the `common type of shift. 'I' have been able to accomplish lthis without the use of coinplicated or extra parts, the manufacturing` cost of my improvementl being substantially the same as required by the usual arrangement.

In the drawings, Fig.' l is a substantially central longitudinal section through my preferred form of shifting mechanism; Fig. 2 is a horizontal sectional plan asindicated by the lines 2 2 on Fig. 1;Fig. 3 is a fragmentary sectional plan as indicated by the line 3 3 on Fig. l; Fig. 4 is a sectional plan similar to Fig. 2 as indicatedby the line stmt provided with shifter heads l0 and ll hav- C ing open inwardly facing throats as indi- Aated at l2 and 13. The headsmay be secured to the respective bars in any manner as by the threaded engagement indicated at l5. I have shown the heads asI bearing against each other along their adjacent surfaces whereby the respective vertical surfaces of each throat may be maintained parallcl tothe other.

The shifter lever guide may be embodiedA in a plate 20, supported by a substantially fiat surface 18 on the casting l, to which the plate is preferably secured as by screws 2l. As illustrated in Fig. 4, the plate is provided with a slot 23 in the nature of an ogee or compound curve, the respective ends of which `gradually curve laterally, one for` wardly and the other rearwardly.' These slots guide the lower end ofthe lever into and out of the throats consequent upon throwing the upper end of the lever torwardly or rearwardly as will be later set out more in detail.

lhe bracket 5 may be supported by side webs 30 on either side of the plate 2() which terminate in a socket portion 3l" for receiving the usual ball portion of the lever G.

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rEhe ball is shown as held in place by an annular member 33 having a spherical surface complementary to the ball.

ln order that the swing of the upper end of the lever may be in a straight path with reference to the operator as contrasted with the usual sideward swing of this lever, as ordinarily employed, l may provide a universal movement between the upper and lower end of the lever. A simple arrangement for accomplishing this may comprise a slot 26 in the ball 32, the lower end of the lever indicated at 27 being set in the slet secured as by a pivot pin 28, to the ball. i'a plate 34 overlying the member 33 is shown as provided with a longitudinal slot which will permit only the rectilinear movement of the portion 27 of the lever, while allowing the lower end to follow the guide.

The lower end of the lever designated extends through the curved slots 28 and is shown as provided with a ball end 3T ranged to engage alternately one of the throats l2 or 13 of the respective shifting head. By reason of the camming action or' the guide slot 23 against the lever, when moved, the path described by this ball end is substantially that indicated in broken lines at A in F ig. 2. In connection with this figure, it will be noted that a verti al surface of each throat has a beveled ci or rounded portion 38 to allow the ball end 37, in being carried from engagement .with one of the throats and into the other, to clear the previously engaged throat without carrying its head forwardly, or rearwarcllj,7 as the case may be, beyond the normal position. By reason of these rounded corners, the ball i is permitted to leave the throat just engaged with a diagonal (forward or rearward) movement, while as soon as the ball has been moved past this corner, a snug engagement between the ball and the other throat for the remainder of the shifting movement is maintained. This feature also permits the heads to be close together, even touching as previous-.ly mentioned, while permitting the easy uni-directional shift.

When the heads are shifted out of the normal position, as the head 1l in Fig. 4, the arm 36 extends downwardly at an angle, and to permit this while maintaining a fairly close contact between the end of the arm and both side surfaces of the throats, l prefer'- ably cut away the upper corner adjacent one of the side surfaces of each throat as at 39.

lt will be understood from the above description, that when the parts are in the position shown in Fig. 4, a rearward swinging of the lever will cause its lower end to bear against the surface 123 of the throat 13 to carry the head ll forwardly, where by reason of the bevel 38 at the opening of the throat 13, the ball will entirely clear the head ll and leave it exactly in the position shown in Fig. 2. et the same time, the bevel 3S on the other head permits the ball 37 to move into the throat 1:2 while guided in a fixed path by reason of the slot 23, with just enough clearance to insure free move ment, and as the guide slot cams thelever over, a reasonably close lit is maintained between both side surfaces of the throat 1Q and the ball.

It is within the spirit of my invention to provide a Aunitary lever as well as that just described, and in this case the compound curve described by the lower end of the lever as limited by the guiding slot when translated to the operating` end of the lever (i, becomes a very gradual one and thus shifting is made by my arrangement an exceedingly simple operation. Moreover, due to the close contact maintained at all times between the lower end of the lever and the respec tive heads, the lever will not be subject to vibration. It will be further seen that manipulation of the lever by reason of the unidirectional movement may be accomplished as rapidly as desired, without danger of strain or excessive wear on the various parts.

fis a safeguard against displacement of either of the heads when disengaged by the lever, and to malte the shifting mechanism more complete in a unit, l preferably provide means whereby when one of the bars is shifted out of its normal position shown in F ig. 2, the other bar will be positively held in place. To this end l. may employ a ball 45, loosely fitting a recess 46 in the bearing portion of the frame. The bars are shown as provided with concave recesses as at 47, oppositely disposed when the bars are in such normal position. TWhen one of the bars is shifted as in Fig. 4, the ball is forced and held in the concavity in the other bar by the plain surface of the shifted bar, where it retains the non-shifted bar against accidental movement in either direction. Such an arrangement will eifectually prevent any damage to the mechanism and further insure precision of operation.

ll] hen combined with a shifting arrangement such as shown in my prior application, Serial No. 15,480, filed March 14th, 1925, the ball arrangement just described may be eliminated. Fig. 5 sho-ws diagramn'iatically the mechanism described and claimed in that application in connection with the gearing adapted to deliver a plurality of speeds. In this ligure, 50 and 5l represent driving and driven members having clutch teeth 52 and 53 respectively. rlhe clutch teeth 52 and 53 are arranged to be engaged by dental clutch members 54 and 54, the former adapted to connect the member 50 with either an intermediate shaft 55 or a gear 56 freely journalled about the shaft. rlhe members 54 and 54 are arranged to slide with reference to their respective teeth 59. or

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53 to allow teeth 57 to shift into engagement with teeth rigid with either the shaft 55 or respective gear members 56 or 67.

llvlhen the heads l and ll of my just described shifting mechanism are both in their rearward position as shown in the diagram, the gear 56 is rotated at the same speed as the driving shaft which in turn rotates an internal-external eccentrically mounted gear member S through gear teeth 59 and 60 at a higher speed, which gear member in turn rotates the intermediate shaft through gear teeth (il and 62 at a still higher speed. In this position of the heads the intermediate shaft 55 is connected directly to the driven shaft, Direct drive is had when both heads 10 and l1 are in the normal position. In this condition the members 54 and 54 connect both the driving and driven members to the intermediate shaft 55. In the third position, with the head 10 shifted forwardly (the other head remaining in the normal position) the driving shaft is still coupled to the intermediate shaft and the driven shaft to the gear 67. Then the gearing operates as an increased speed transmission, power being delivered through the intermediate shaft and gears G2 and 6l to the member 5S, which through the gear teeth 65 and 66 drives the member (37 now connected with the driven shaft.

The bars 8 and it are each resiliently connected to their respective clutch members 54 or 53 by a pair of coil springs 70 and 7l,`

each arranged to bear against one end of a shackle member 72 connected as by a shifter linger 73 to the respective clutch members fl or 54. This shackle member carries a wedge shaped point 74 arranged to cam against a similarly wedge shaped plunger 75 to retract the plunger whenever the member TQ is being shifted from one position to another.

In operation, assuming` the bar l is shifted forwardly from the position shown in the dagran'i, the spring 7l will first be compressed by a block 77 rigid with the bar and further movement will cause the plunger 75 to be cannned outwardly until the wedge points are aligned upon which the spring 7l will expand and push the shackle member beyond this dead center position. rI`he spring of the plunger then acts to cam the shackle member still further to the right and to hold the member 72 against an abutment 79, thus holding the bar 3 against shifting out of its new position. Similar abutments 7i) are provided to limit both the forward and backward moven'ient of each shackle member thus insuring the heads l() and ll of the previously described shifting mechanism being` maintained in their proper relation to the movement of the shifter lever (i.

It will be seen that I have provided a gear shifting mechanisn'i which will operate while keeping within the spirit of my in-` vention and do not therefore wish to limit myself to the particular embodiment shown.

Having thus described my invention, I claim:

l. In combination, in a gear shifting mechanism, means for effecting the longitudinal shifting of a pair of members from f normal position, a curved guide for sait, means whereby such shifting may be accomplished by a general forward or rearward movement of the shifting means, manually operated means connected to the rst named means, another guide for controlling the movement of the manual operating means whereby said latter means moves only in a rectilinear path.

2. In combination, a pair of members arranged to be shifted one forwardly and the other rearwardly from a given position, and means arranged to engage the members alternately and pass from one to the other, while both members are in said given position, said means including a curved guide whereby the shifting movement may be in a single general direction.

3. In combination, a pair of longitudinally shift-able members, and an operating member selectively cooperating therewith, and a guide for the operating member com prising a plate having a compound curved slot embracing the operating member.

et. In combination, a pair of men'ibers to be shifted, one of said n'iembers being arranged to be shifted forwardly, the other rearwardly, abutment surfaces carried by each of said members, and a shifting member arranged to engage alternately the abutment surfaces of the respective members, and means including a guide in the form of a double curve, whereby the guide cams the shifting member out of engagement with the abutment surface on one member to be shifted and into engagement with the other.

5. Incombination, a pair of members to be longitudinally shifted, abutn'ient surfaces carried by each of said members, and a shifting member arranged to engage alternately the abutment surfaces of the respective members, and means im'lnding a guide in the form of a double curve, whereby the guide cams the shifting member out of engagement with the abutment surface on one member to be shifted and into engagement with the other, consequent upon a general forward or rearward movement of said shifting inember.

6. In combination with a gear shift, a pair of members to be longitudinally shifted, each of members having an abutlili) lll) nient surface, a guide, and means cooperating with the guide and engaging the abutment surfaces alternately, said guide being in the nature ot' a compound curve'having a portion intermediate its ends extending at the greatest angle to the axes ot the members, and means whereby said shitting means may-be moved in a single general direction along the curve and disengage one ot the abutment surfaces at the intermediate portion of the curve, and engage the' other.

i'. in combination with a gear Shifting mechanism, a pair ot' members to be shifted, throats in said members facing toward each other, a men'iber extending into position to engage either or' said throats to carry the selected member torwarr ly or rearwardly, and opposed 'curved cam surfaces to translate a general longitudinal movement or said engaging member into a transverse movement into and out ot the desired throat.

r. In combination, a pair ot' longitudinally shiitable members, a shitting lever selectively cooperating therewith, and a guide tor said lever in the nature ot' an ogee curve, having its end portions extending in the general direction ot the axes ot the shittal'ile members and the internaaliate portion` at an acute angle relative thereto, whereby an abrupt cam surface is had to move the shitting member quickly trom one shittable member to the other at the intermediate zone when the lever is swung in a direction parallel to said axes.

9. ln combination, a pair ot members each provided with throats facing toward each other, an operating member adapted to selectively engage the throats, and a guide tor the opi-mating member arranged to cam the eperating member out of engagement with one ot' the throats and into'engagement with the other, and means including a rounded corner on each oit' the throats, whereby the shift from one throat to another may be in a diagonal path, and whereby when the operating member is moved past the rounded corner, a close engagement between the throat and opposite sides ot the operating member is maintained.

l0. In combination with a pair ot shittable bars, each provided with an open throat, a lever arranged to selectively enter the throat to shi'tt the bars, means for gradually cannning the lever out of engagement with one ot the throats and into engagement with the other when the lever is swung toi-wart ly or rearwardly, and means tor holding the non-shifted bar against accidental movement while the lever is engaging the other bar.

il. In combination with a. pair ot shittable bars, each provided with an open throat, a member ai anged to selectively enter the throats to shift the bars, means l'or camming said member out of engagement with one of the throats and into engagement with the other when said member is moved forwardly or rearwardly, and resilient means for holding the non-shifted bar against accidental movement while the member is engaging the other bar.

l2. ln combination, in a gear shitting mecha nism` a pair et bars to be shifted, open throats arried by each of' said bars, a lever arranged to selectively engage the throat, a cam guiding slot i'or directing the path ol the lever into and out ot the throats, and means whereby the upper end oit the lever may be guided iu a straight path irrespective ot' transverse movement ot the lower end ol the lever.

lil. tu combination, with a gear :'-rl'iiiting member, a iframe, a pair ot bars suliported by the trame and arranged to be shitted longitudinally relative thereto, an abutment carried by each ot the bars, an operating lever pivoted to the trame and arranged to selectively engage the abutment, a guide in the nature ot a 'am for causing the lever to disengage the abutment ou one ot the bars and to engage the other consequent upon the lever being moved7 and n'ieans associated with the pivot., whereby the lower end oi the lever may have .longitudinal and transverse movement, while the upper end ot the lever is guided in a straight path.

In testiniony whereof, l hereunto a'liix my signature.

CHARLES lu. l?. Al'lLh/I. 

